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Rechargable Batteries

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Well-Known Member

I think it was 2 years ago I ask, which rechargeable battery is best, I am having trouble finding good batteries. I was told, buy enelope so I did.

Batteries have been working good until now. I use 2 AA batteries in the digital camera an 2 in the electric tooth brush. Camera batteries need to be charged about every 2 weeks. Tooth brush needs to be charged every 4 months. I always let batteries go dead before recharging.

I use to be able to take 500 pictures and several videos with the camera batteries for 2 weeks but now batteries go dead in 10 minutes.

Electric tooth brush holds a charge for 4 months before needing to be recharged.

I had to swap batteries from tooth brush to camera so I can use the camera.

Battery charger is Rayvac PS13 2.8vdc 160ma.

AA Batteries are 1.2v 1900 mAh

Question. Is it typical that batteries that get used the most go bad first?

Active Member

Also, although NiMH are often claimed to have no memory effect, they still do in my experience.
That is, if they are not usually completely discharged, the crystal structure of the plates changes in the parts that are never used and the internal resistance goes up when you get to the "normal" discharge point.

With something that needs high current like a camera, that can cause it to indicate the batteries are flat.

Try connected eg. a ten ohm resistor across each cell and leave them for about a week, then fully charge them and try them again.
I've found that frequently brings them back to life, by discharging them past the high resistance point so the full depth of the plates gets reformed on the next charge.

(And you can ignore the usual rule of not discharging below 1V/Cell. That applies to cells in a pack, to avoid reverse polarising any weak ones.
By discharging each cell separately, that cannot happen).

Well-Known Member

Your Rayvac charger is probably a poorly designed Chinese copy of a real Rayovac one. The Rayovac charger is cheap junk. I have one (model PS13) that I found in the trash. It does not detect a full charge then shutoff so it keeps over-charging which is a death sentence for Ni-MH cells. My over-charging cells become fairly warm. Note that its 160mA charging current will fully charge your 1900mAh Eneloop cells in 12 hours but maybe you are charging for only 7 or 8 hours, then they are never fully charged.

The Japanese Eneloop cells hold their charge for 1 year so American Energizer and Duracell for the last 5 years buy then sell the Japanese ones.

I have a Duracell charger that charges correctly. It charges two AA Ni-MH cells at 1550mA or four cells at 775mA, detects full charge then shuts off with a green light.

Well-Known Member

yes, it is typical for batteries used the most to fail more often. a rechargeable battery works by undergoing a chemical reaction when charging, and that reaction being reversed when it discharges. the electrodes in the battery are made of metal that undergo redox (reduction-oxidation) reactions where the metal forms a compound during the oxidation portion of the cycle, and plates back out during the reduction portion of the cycle. the problem is, that when the metal plates out, not all of it precipitates on the electrode. the result is that there are metal particles suspended in the electrolyte, and they are nonrecoverable. it is the amount of metal on the electrode that directly impacts the battery capacity. a side effect of this is some of the suspended particles of metal can eventually string together and form a short circuit between the electrodes (some electrode metals also tend to grow "whiskers" which are crystals of the metal).

Well-Known Member

Make sure you have a good charger, that shuts down when it the battery is charged, as AG noted.
Overcharging will significantly shorten the life of a NiMh cell much more than the old NiCDs, which were more tolerant of overcharging..

Zapper
Curmudgeon Elektroniker
--The important thing about having knowledge is knowing where it correctly applies..--

Well-Known Member

What batteries were the camera and toothbrush originally designed for? Were they designed for use with 1.5 volt AA batteries or the 1.2 volt rechargeable batteries you are using? That said, as mentioned, a good charger is needed as overcharge is a death sentence for the batteries, especially the type you have.

Ron

Please do not PM me with forum related questions. Let's keep things in the open forum. Thank you.

Well-Known Member

What do you recommend for a battery charger that will not over charge a AA battery? It needs to be small light weight for camping and traveling I have a 120 volt AC outlet on the dash of my vehicle it needs to plug into as we drive on the highway.

Well-Known Member

You may want to give this a read: Overview of Rechargeable Batteries and Fast Stand-Alone Chargers. Next you may want to consider that the 120 VAC outlet on your vehicle's dash is likely a MSW (Modified Sine Wave) outlet and not a TSW (True Sine Wave) outlet so whatever charger you choose needs to work with the MSW you have. Most 120 VAC inverters are the less expensive MSW output rather than a more expensive TSW type. A good charger will discharge a partially charged battery before starting a charge process and when the battery is close to full charge reduce the charge to a float charge. As to a specific brand I have no good suggestion but I would look for one with the features mentioned in the link. I would also, as mentioned, make sure whatever you choose it is compatible with whatever your vehicle inverter system is.

Ron

Please do not PM me with forum related questions. Let's keep things in the open forum. Thank you.

Well-Known Member

What batteries were the camera and toothbrush originally designed for? Were they designed for use with 1.5 volt AA batteries or the 1.2 volt rechargeable batteries you are using? That said, as mentioned, a good charger is needed as overcharge is a death sentence for the batteries, especially the type you have.

Tooth brush came with alkaline batteries they run the brush fast at first but as batteries get used the brush runs slower and slower until it is too slow. Rechargeable battery keeps the brush running full speed when it suddenly looses speed too slow to use then batteries get recharged.

Camera came with no batteries directions said to use alkaline or rechargeable battery. $1 alkaline battery don't last long maybe 40 pictures. The better over priced Energizer batteries will do about 120 pictures. The rechargeable battery is best it does 400 pictures and several videos too.

LINK has very good information about batteries. The part number are all for IC chips to build a battery charger. I need a ready built battery charger so far not finding any with information how they work. I have not found one yet that says it does a deep charge by discharging the battery before. recharges it.

Well-Known Member

What do you recommend for a battery charger that will not over charge a AA battery? It needs to be small light weight for camping and traveling I have a 120 volt AC outlet on the dash of my vehicle it needs to plug into as we drive on the highway.

A few years ago at Costco I bought a Duracell CEF27NA2 charger that came with four Duracell AA made in Japan Eneloop type of Ni-MH cells. It is a smart fast charger that detects a full charge then shuts off.
But it is might not work properly with the Mickey Mouse squarewave waveform of a cheap inverter since it relies on the higher peak voltage of a normal mains sinewave. Maybe your Rayovac charger also needs the higher peak voltage plus its charge takes many hours so from an inverter it never fully charges your batteries.

Well-Known Member

On Energizer battery company's website at the bottom of the home page you click on Technical Info where you can click on Battery Handbooks. The Ni-MH handbook says the same as what www.batteryuniversity says.
1) You do not need to discharge a Ni-MH battery before charging unless you have a cheeeep charger that is simply a timer.

Well-Known Member

A few years ago at Costco I bought a Duracell CEF27NA2 charger that came with four Duracell AA made in Japan Eneloop type of Ni-MH cells. It is a smart fast charger that detects a full charge then shuts off.
But it is might not work properly with the Mickey Mouse squarewave waveform of a cheap inverter since it relies on the higher peak voltage of a normal mains sinewave. Maybe your Rayovac charger also needs the higher peak voltage plus its charge takes many hours so from an inverter it never fully charges your batteries.

Most of the time I will charge batteries at home. 20% of the time I will charge batteries at the camp ground. About .05% of the time I might want to charge while driving but if it won't work then I will remember not to charge batteries in vehicle. I bought a new Chevy Tahoe PPV police cruiser with tow package to pull the RV. It has off road suspension, over size brakes, bullet proof glass, built in row bars, 2 12v batteries under the hood 1 is just for the trailer. Places to plug in computers and all kinds of equipment and 120 volt ac outlet. Maybe I can test the outlet with scope to see if it is sine wave. This vehicle is a problem I set cruise control on 65 mph get in right lane set back and relax and let people pass me speed limit is 70. People come flying around 80 mph hour see the vehicle then slam on the brakes and drive right next to me and cause a traffic jam, 20 min later there are 200 cars behind us. I'm not the idiot causing the problem there is nothing I can do to make the other vehicle move on. If traffic jam gets bad enough I pull off at the next rest stop that could be 50 miles away. This vehicle might have better than average DC to AC inverter. Lots of vehicles get mad and pass us on the right shoulder. I will shop for a good battery charger.

Well-Known Member

I think it was 2 years ago I ask, which rechargeable battery is best, I am having trouble finding good batteries. I was told, buy enelope so I did.

Batteries have been working good until now. I use 2 AA batteries in the digital camera an 2 in the electric tooth brush. Camera batteries need to be charged about every 2 weeks. Tooth brush needs to be charged every 4 months. I always let batteries go dead before recharging.

I use to be able to take 500 pictures and several videos with the camera batteries for 2 weeks but now batteries go dead in 10 minutes.

Electric tooth brush holds a charge for 4 months before needing to be recharged.

I had to swap batteries from tooth brush to camera so I can use the camera.

Battery charger is Rayvac PS13 2.8vdc 160ma.

AA Batteries are 1.2v 1900 mAh

Question. Is it typical that batteries that get used the most go bad first?

Try to count the number of times you recharged, that is equal to 1 cycle if you drain them most of the way down before recharging.
The count is somewhere between 1000 and 2000 cycles.
Two years has 365 days times 2 which is 730 days. If you charged them once per day they should still be good. If you charged them two times a day it may be getting time to get new ones.
None of the cells last forever. The newer Eneloops are supposed to go for more cycles.

One test is worth a thousand expert opinions, but one expert specification is worth a thousand tests.
Mathematics is the shortcut to understanding nature.
If i miss something you posted or something you think is important, feel free to PM me.

Well-Known Member

Try to count the number of times you recharged, that is equal to 1 cycle if you drain them most of the way down before recharging.
The count is somewhere between 1000 and 2000 cycles.
Two years has 365 days times 2 which is 730 days. If you charged them once per day they should still be good. If you charged them two times a day it may be getting time to get new ones.
None of the cells last forever. The newer Eneloops are supposed to go for more cycles.

Been there and done that. My electric toothbrush sits in a charger and that thing must be 7 or 8 years old. Still working. My wife bought me a battery powered one using two AA batteries for when we travel. Since a few AA Alkaline batteries last so long I never gave any thought to using rechargable batteries in it. Both are Oral B I think.

Years ago I had a Nikon Coolpix 900 which used 3 AA batteries. I feel your pain on that note. That camera literally ate batteries. Using the flash was an even larger train wreck. I literally dragged around a dozen batteries in my camera bag. Even using high capacity rechargable batteries was a pain. That was long ago and I never looked back. Still have the camera but haven't used it in years, maybe 15 years. I now use a camera with a designed rechargable battery and only keep a few in my bag. By today's standards that old Nikon would be junk anyway.

Ron

Please do not PM me with forum related questions. Let's keep things in the open forum. Thank you.

Well-Known Member

Been there and done that. My electric toothbrush sits in a charger and that thing must be 7 or 8 years old. Still working. My wife bought me a battery powered one using two AA batteries for when we travel. Since a few AA Alkaline batteries last so long I never gave any thought to using rechargable batteries in it. Both are Oral B I think.

Years ago I had a Nikon Coolpix 900 which used 3 AA batteries. I feel your pain on that note. That camera literally ate batteries. Using the flash was an even larger train wreck. I literally dragged around a dozen batteries in my camera bag. Even using high capacity rechargable batteries was a pain. That was long ago and I never looked back. Still have the camera but haven't used it in years, maybe 15 years. I now use a camera with a designed rechargable battery and only keep a few in my bag. By today's standards that old Nikon would be junk anyway.

Looks like it has a good sensor in it though and 16MP isnt that bad although yeah there are higher now.
83x optical zoom is nice too. I rarely use my zoom though (Canon).

One test is worth a thousand expert opinions, but one expert specification is worth a thousand tests.
Mathematics is the shortcut to understanding nature.
If i miss something you posted or something you think is important, feel free to PM me.